Methods for monitoring ablation progress with doppler ultrasound

ABSTRACT

Systems and methods for treating tissue are disclosed. The target tissue is ablated. A real-time image of the target tissue is generated during the ablation. The real-time blood perfusion level of the target tissue is determined from the real-time image and compared to an initial blood perfusion level of the target tissue. The comparison provides a metric for the progress of the ablation, and ablation is halted when the real-time blood perfusion drops below a threshold level relative to the initial blood perfusion level.

CROSS-REFERENCE

This application is a continuation of PCT Application No.PCT/US18/30295, filed Apr. 30, 2018; which claims the benefit of U.S.Provisional Application No. 62/501,238, filed May 4, 2017; whichapplications are incorporated in their entirety herein by reference.

BACKGROUND OF THE INVENTION 1. Field of the Invention

The present invention relates generally to medical methods andapparatus. More particularly, the present invention relates to methodsand systems for displaying in real-time an image of tissue to be treatedsuch that the treatment can be controlled.

Current medical treatments of organs and tissues within a patient's bodyoften use a needle or other elongate body for delivery of energy,therapeutic agents, or the like. Often, the methods use ultrasoundimaging to observe and identify a treatment target before, during,and/or after.

Of particular interest to the present invention, a treatment for uterinefibroids has recently been proposed which relies on the transvaginal orlaparoscopic positioning of a treatment probe or device in the patient'suterus. A radiofrequency or other energy or therapeutic delivery needleis deployed from the device in proximity to or directly into thefibroid, and energy and/or therapeutic substances are delivered in orderto ablate or treat the fibroid. To facilitate locating the fibroids andpositioning the needles within the fibroids, the treatment deviceincludes an ultrasonic imaging array with an adjustable field of view ina generally forward or lateral direction relative to an axial shaftwhich carries the needle. The needle is advanced from the shaft andacross the field of view so that the needle can be visualized anddirected into the tissue and the targeted fibroid.

While effective and very beneficial for patients, such needle ablationand treatment protocols face several challenges. While the position ofthe needle can be observed on the ultrasonic or other visual image, thetreatment volume resulting from energy or other therapeutic delivery canbe difficult to predict. One of reasons may be that the energypropagation within the tissue may largely depend on the tissue structureand the distribution of blood vessels which can act as “heatsinks.” Thecoagulation sizes introduced by RF ablation may vary from tumor to tumorbecause of the distribution of the blood vessels. Current coagulationsize and safety margin are typically based on a static size predictionwhich could affect the efficacy and even safety of the treatment. Theexperience of the physician can help to determine an appropriate endpoint for the ablation, but it would be desirable to reduce the need toexercise judgment and conjecture.

Tissue heating or cooling may be affected by adjacent vasculature, asblood vessels can dissipate thermal energy and cause variation on thecalculated coagulation size. Thus, thermal ablation size and cytotoxiceffectiveness may decrease with the proximity and the size of adjacentvessels. Increased local recurrence rates of tumors adjacent to largevessels (>3 mm) can demonstrate the significant effect of thermal energysinks. The distortion of the perivascular margin may be presentapproximately one-third of the ablations. The extent of the heat sinkeffect may significantly correlate with the size of the vessel. Multiplestudies have also examined the effects of modulating hepatic perfusionand have found that the ablation size increases with decreased bloodflow. Developing methods to better estimate or monitor the ablation sizewill be beneficial to both efficacy and safety of treatments.

For these reasons, it would be desirable to provide improved systems andmethods for the deployment of energy delivery and other needles withinultrasonic or other imaging fields of view in energy delivery or othertherapeutic protocols. It would be particularly useful to provide thetreating physician with information which would assist determining thereal-time progress of the ablation. It would also be desirable toprovide feedback to the physician to assist in accurately predicting atreatment volume. Such information should allow the physician, ifnecessary, to end an ablation protocol at an appropriate time when thedesired target tissue has been fully or near fully ablated whileunintentional ablation of non-target tissue is reduced. Furthermore, itwould be desirable to provide feedback to the physician allowing thephysician to assess a safety margin so that sensitive tissue structuresare not damaged. All such feedback or other information is preferablyprovided visually on the ultrasonic or other imaging screen so that thephysician can start, pause, and stop the treatment. At least some ofthese objectives will be met by the inventions described hereinafter.

2. Description of the Background Art

Ultrasound (US) is the primary imaging modality used to evaluatepatients in whom the presence of uterine fibroid tumors is suspected.Trans-abdominal and transvaginal US are used in conjunction with colorand pulsed Doppler US. Doppler US can be used to assess fibroid anduterine vascularity and flow patterns. Typically, uterine fibroid tumorshave a marked peripheral blood flow (perifibroid plexus) and decreasedcentral flow. The resistance index is usually decreased in theperifibroid plexus, compared with that in the surrounding normalmyometrium.

Contrast-enhanced ultrasound (CEUS) is a technique that makes use ofmicrobubble-based contrast agents to improve the echogenicity of bloodand thus improve the visualization and assessment of cardiac cavities,large vessels and tissue vascularity. Ultrasound contrast agents offerhigh sensitivity with a safety profile. CEUS offers additionaladvantages over the alternative imaging modalities. It can be performedimmediately after baseline ultrasound, the first-line imaging modalityin many clinical settings, and it can be carried out in a variety ofscenarios (clinical office setting, operating room, etc.). It does notinvolve exposure to ionizing radiations, and it allows prolonged realtime examinations where also rapid changes can be captured, or the studyrepeated if needed.

References that may be of interest include: U.S. Pat. No. 5,979,453 toSavage et al., U.S. Pat. No. 6,602,251 to Burbank et al., U.S. Pat. No.7,918,795 to Grossman [Attorney Docket No. 31992-703.201], U.S. Pat. No.8,506,485 to Deckman et al. [Attorney Docket No. 31992-706.301], U.S.Pat. No. 8,992,427 to Munrow et al. [Attorney Docket No. 31992-714.202],and U.S. Pat. No. 9,517,047 to Grossman [Attorney Docket No.31992-704.301].

SUMMARY OF THE INVENTION

The present disclosure provides systems and methods for treating tissuestructures. In particular, systems and methods for ablating tissuestructures and monitoring the ablation are provided. A real-time imageof a target tissue structure, such as a uterine fibroid, may bedisplayed. The real-time image may also show the blood flow and/orperfusion within the target tissue structure. For example, the real-timeimage may comprise a Doppler ultrasound image and/or a contrast enhancedultrasound imaging (CEUS) to show the blood perfusion. The image showingthe blood perfusion may be overlaid with an image showing the morphologyand/or density of the target tissue structure. As the target tissue isablated, the blood perfusion of the target tissue may be reduced and/orthe size of the reduced blood perfusion area may be increased. Bydisplaying to the physician or user a real-time image of the targettissue showing the tissue morphology and blood perfusion duringablation, the physician or user can track the progress of the treatment.For instance, once the blood perfusion of the target is reduced by athreshold amount as compared to its initial blood perfusion level and/oronce the size of the reduced blood perfusion area reaches a thresholdsize, the user may halt the ablation to ensure that the target tissuestructure is fully or near fully ablated and the undesired ablation ofnon-targeted is minimized. Furthermore, the effectiveness and safety ofthe treatment may be ensured by displaying the real-time image of thetarget tissue, which can allow the movement of perfusion boundaries, theeffective edge of ablation, to be monitored in real-time.

Aspects of the present disclosure provide exemplary methods of treatinga target tissue. The target tissue may be ablated. A real-time image ofthe target tissue may be generated during the ablating. The image mayshow blood perfusion of the target tissue as the target tissue isablated. The image showing blood perfusion of the target tissue may bedisplayed, thereby indicating to a user a progress of the ablation.

A real-time blood perfusion level of the target tissue may bedetermined, and it may be determined whether the real-time bloodperfusion level is below a threshold amount. An initial blood perfusionlevel of the target tissue may be determined, and the threshold amountmay be 50% or less, 45% or less, 40% or less, 35% or less, 30% or less,25% or less, 20% or less, 15% or less, 10% or less, or 5% or less of theinitial blood perfusion level of the target tissue. The user may beindicated or instructed to halt the ablating of the target tissue inresponse to the real-time blood perfusion level being below thethreshold amount. Alternatively or in combination, the ablating of thetarget tissue may be halted, for example, automatically halted, inresponse to the real-time blood perfusion level being below thethreshold amount. The initial blood perfusion level may comprise aninitial Doppler ultrasound signal within the target tissue, and thereal-time blood perfusion level may comprise a real-time Dopplerultrasound signal within the target tissue.

A position of an imaging source may be fixed in relation to the targettissue. The real-time image of the target tissue may be generated duringthe ablating with the position of the imaging source fixed in relationto the target tissue. The target tissue may be ablated with an ablationelement. The imaging source may be fixedly coupled to the ablationelement. Alternatively or in combination, the imaging source may beremovably coupled to the ablation element.

The real-time image of the target tissue may be generated by generatingat least one ultrasound image of the target tissue. The at least oneultrasound image may comprise one or more of a contrast enhancedultrasound image, a B-mode ultrasound image, or a Doppler ultrasoundimage. The at least one ultrasound image may comprise a B-modeultrasound image and a Doppler ultrasound image overlaid over oneanother. Common anatomical markers in the two images may be identifiedand mapped to one another to generate the overlaid image. In some cases,a contrast agent may be introduced into the target tissue prior to theablation to provide more enhanced ultrasound images.

The target tissue may be ablated with one or more of RF energy, thermalenergy, cryo energy, ultrasound energy, HIFU energy, optical energy,laser energy, X-ray energy, or microwave energy. The target tissue maybe ablated by extending at least one ablation element into the targettissue. The at least one ablation element may comprise one or more of atleast one needle or at least one tine. The target tissue may comprise afibroid, a uterine fibroid, a fibroid tissue, a tumor, a tissuehyperplasia, or an undesired scar tissue.

Aspects of the present disclosure provide further methods of treating atarget tissue. The target tissue may be ablated. The progress of theablating of the target tissue may be monitored by viewing a real-timeimage of the target tissue to monitor blood perfusion of the targettissue.

To monitor the progress of the ablating of the target tissue by viewingthe real-time image of the target tissue to monitor blood perfusion ofthe target tissue comprises, an initial blood perfusion level of thetarget tissue may be determined, a real-time blood perfusion level ofthe target tissue may be determined, and the initial and real-time bloodperfusion levels of the target tissue may be compared. To compare theinitial and real-time blood perfusion levels of the target tissue, itmay be determined whether the real-time blood perfusion level of thetarget tissue is below the initial blood perfusion level by a thresholdamount. The ablating of the target tissue may be halted once the bloodperfusion of the target tissue is below the threshold amount. Thethreshold amount may be 50% or less, 45% or less, 40% or less, 35% orless, 30% or less, 25% or less, 20% or less, 15% or less, 10% or less,or 5% or less of an initial blood perfusion amount of the target tissue.The initial blood perfusion level may comprise an initial Dopplerultrasound signal within the target tissue. The real-time bloodperfusion level may comprise a real-time Doppler ultrasound signalwithin the target tissue.

A position of an imaging source in relation to the target tissue may befixed. The real-time image of the target tissue may be generated duringthe ablating with the position of the imaging source fixed in relationto the target tissue. The target tissue may be ablated with an ablationelement. The imaging source may be fixedly coupled to the ablationelement. Alternatively or in combination, the imaging source may beremovably coupled to the ablation element.

The real-time image of the target tissue may comprise at least oneultrasound image of the target tissue. The at least one ultrasound imagemay comprise one or more of a contrast enhanced ultrasound image, aB-mode ultrasound image, or a Doppler ultrasound image. The at least oneultrasound image may comprise a B-mode ultrasound image and a Dopplerultrasound image overlaid over one another. Common anatomical markers inthe two images may be identified and mapped to one another to generatethe overlaid image. In some cases, a contrast agent may be introducedinto the target tissue prior to the ablation to provide more enhancedultrasound images.

The target tissue may be ablated with one or more of RF energy, thermalenergy, cryo energy, ultrasound energy, HIFU energy, optical energy,laser energy, X-ray energy, or microwave energy. The target tissue maybe ablated by extending at least one ablation element into the targettissue. The at least one ablation element may comprise one or more of atleast one needle or at least one tine. The target tissue may comprise afibroid, a uterine fibroid, a fibroid tissue, a tumor, a tissuehyperplasia, or an undesired scar tissue.

Aspects of the present disclosure also provide systems for treating atarget tissue. A treatment system may comprise a treatment probe, areal-time display, and a controller. The treatment probe may comprise ahandle, a probe body, an imaging source coupled to the probe body, andan ablation element coupled to the probe body and configured to ablatethe target tissue. The real-time display may be coupled to the treatmentprobe. The controller may be coupled to the imaging source of thetreatment probe and the real-time display. The controller may comprise acomputer readable, non-transient storage medium comprising (i)instructions for the imaging source to generate a real-time image of thetarget tissue during ablation of the target tissue and (ii) instructionsfor the real-time display to display the real-time image, the real-timeimage showing blood perfusion of the target tissue, thereby indicatingto a user a progress of the ablation.

The ablation element may comprise a needle structure extendable from thetreatment probe into the target tissue. The ablation element may furthercomprise a plurality of needles extendable from the needle structureinto the target tissue. The computer readable, non-transient storagemedium may further comprise instructions for the real-time display todisplay a representation of a position of one or more of the needlestructure or the plurality of tines on the real-time image.

The computer readable, non-transient storage medium may further compriseinstructions for determining a real-time blood perfusion level of thetarget tissue and determining whether the real-time blood perfusionlevel is below a threshold amount. The computer readable, non-transientstorage medium may further comprise instructions for determining aninitial blood perfusion level of the target tissue. The threshold amountmay be 50% or less, 45% or less, 40% or less, 35% or less, 30% or less,25% or less, 20% or less, 15% or less, 10% or less, or 5% or less of theinitial blood perfusion amount of the target tissue. The computerreadable, non-transient storage medium may further comprise instructionsfor indicating to the user to halt the ablating of the target tissue inresponse to the real-time blood perfusion level being below thethreshold amount. The initial blood perfusion level may comprise aninitial Doppler ultrasound signal within the target tissue. Thereal-time blood perfusion amount may comprise a real-time Dopplerultrasound signal within the target tissue.

A position of an imaging source in relation to the target tissue may befixed. The real-time image of the target tissue may be generated duringthe ablating with the position of the imaging source fixed in relationto the target tissue. The target tissue may be ablated with an ablationelement. The imaging source may be fixedly coupled to the ablationelement. Alternatively or in combination, he imaging source may beremovably coupled to the ablation element.

The real-time image of the target tissue may comprise at least oneultrasound image of the target tissue. The at least one ultrasound imagemay comprise one or more of a contrast enhanced ultrasound image, aB-mode ultrasound image, or a Doppler ultrasound image. The at least oneultrasound image may comprise a B-mode ultrasound image and a Dopplerultrasound image overlaid over one another. Common anatomical markers inthe two images may be identified and mapped to one another to generatethe overlaid image. In some cases, a contrast agent may be introducedinto the target tissue prior to the ablation to provide more enhancedultrasound images.

The target tissue may be ablated with one or more of RF energy, thermalenergy, cryo energy, ultrasound energy, HIFU energy, optical energy,laser energy, X-ray energy, or microwave energy. The target tissue maybe ablated by extending at least one ablation element into the targettissue. The at least one ablation element may comprise one or more of atleast one needle or at least one tine. The target tissue may comprise afibroid, a uterine fibroid, a fibroid tissue, a tumor, a tissuehyperplasia, or an undesired scar tissue.

INCORPORATION BY REFERENCE

All publications, patents, and patent applications mentioned in thisspecification are herein incorporated by reference to the same extent asif each individual publication, patent, or patent application wasspecifically and individually indicated to be incorporated by reference.

BRIEF DESCRIPTION OF THE DRAWINGS

The novel features of the invention are set forth with particularity inthe appended claims. A better understanding of the features andadvantages of the present invention will be obtained by reference to thefollowing detailed description that sets forth illustrative embodiments,in which the principles of the invention are utilized, and theaccompanying drawings of which:

FIG. 1 is a schematic illustration of the system of the presentdisclosure comprising a system controller, an image display, and atreatment probe having a deployable needle structure and imagingtransducer.

FIG. 2 is a perspective view of the treatment probe of the presentdisclosure.

FIG. 3 is a view of the treatment probe of FIG. 2 illustrating animaging component of the probe separated from a needle component withportions broken away and portions enlarged.

FIG. 3A illustrates a distal end of the needle component being connectedto a distal end of the imaging component.

FIG. 4 illustrates a schematic view of the treatment probe of thepresent disclosure.

FIG. 5 illustrates a distal portion of the treatment probe introducedinto a uterine cavity to image a fibroid in the myometrium.

FIGS. 6A, 7A, 8A, 9A, 10A, and 11A illustrate “screenshots” of thereal-time image display as treatment and safety boundaries are beingadjusted and the ablation elements of the treatment probe are advancedinto target tissue, in accordance with the principles of the presentdisclosure.

FIGS. 6B, 7B, 8B, 9B, 10B, and 11B illustrate manipulation of the handlewhich corresponds to the repositioning of the projected images of thetreatment and safety boundaries on the real-time images of FIGS. 6A, 7A,8A, 9A, 10A, and 11A, respectively.

FIG. 12 illustrates a system diagram where a B-mode ultrasound datastream (showing tissue morphology) is combined with a Doppler modeultrasound data stream to generate a real-time image, according to thepresent disclosure.

FIG. 13 illustrates a flow chart of a method of treating tissue,according to the present disclosure.

FIGS. 14A, 14B, 14C, and 14D illustrate various real-time images of atarget tissue structure as it is ablated, according to the presentdisclosure.

DETAILED DESCRIPTION OF THE INVENTION

As illustrated in FIG. 1, a system 10 constructed in accordance with theprinciples of the present invention may include a system controller 12,an imaging display 14, and a treatment probe 16. The system controller12 will typically be a microprocessor-based controller which allows bothtreatment parameters and imaging parameters to be set in a conventionalmanner. The display 14 will usually be included in a common enclosure 18together with the controller 12, but could be provided in a separateenclosure. The treatment probe 16 may include an imaging transducer 20which may be connected to the controller 12 by an imaging cord 24. Thecontroller 12 may supply power to the treatment probe 16 via a treatmentcord 22. The treatment probe 16 may also be in communication with thecontroller 12 via the treatment cord 22 such as to provide one or moreof a control signal, a feedback signal, a position signal, or a statussignal, to name a few. The controller 12 will typically further includean interface for the treating physician to input information to thecontroller 12, such as a keyboard, touch screen, control panel, mouse,joystick, directional pad (i.e., a D-pad), or the like. Optionally, atouch panel may be part of the imaging display 14. The energy deliveredto the treatment probe 16 by the controller 12 may be radiofrequency(RF) energy, microwave energy, a treatment plasma, heat, cold (cryogenictherapy), or any other conventional energy-mediated treatment modality.Alternatively or additionally, the treatment probe 16 could be adaptedto deliver drugs or other therapeutic agents to the tissue anatomy to betreated. In some embodiments, probe 16 plugs into an ultrasound systemand into a separate radio frequency (RF) generator. An interface lineconnects the ultrasound system and the RF generator.

Referring now to FIGS. 2 and 3, the treatment probe 16 may comprise aneedle component 26 and an imaging component 28. The needle component 26and the imaging component 28 may be constructed as separate units orassemblies which may be removably attached to each other for use. Afteruse, the needle component 26 may be separated and will typically bediscarded while the imaging component 28 may be sterilized for reuse.The treatment probe 16 is shown in its fully assembled configuration inFIG. 2 and is shown in its disassembled configuration in FIG. 3. Inother embodiments of the present invention, the needle component 26 andthe imaging component 28 could be combined in a single, integratedhandle unit.

The needle component 26 may comprises a handle portion 27 having acontrol element 30 on its upper surface. The control element 30 maycomprise a joystick, a directional pad (i.e., D-pad), or other userinterface. The control element 30 may be in communication with thecontroller 12 to adjust the display 14, adjust treatment parameters,adjust the size and/or position of the targeting region and/or thesafety region which are shown on the display 14, and/or perform otherfunctions as will be described in more detail below.

The needle 56 may be deployed from the needle shaft 34, and the needle56 and optional tines 57 together may form a needle structure which maybe constructed, for example, as previously described in commonly ownedU.S. Pat. Nos. 8,992,427, 8,206,300, and 8,262,574, the full disclosuresof which are incorporated herein by reference.

The handle portion 27 of the needle component 26 may further include afluid injection port 32 which allows saline or other fluids to beinjected through the needle shaft 34 into a target region in the tissuebeing treated, such as the uterus. The needle handle 27 may also includea needle slide 36, a needle release 38, and a tine slide 40 which areused to deploy the needle 56 and tines 57. The needle slide 36 may beslid forward to advance the needle 56 and may be slid backward toretract the needle 56. The tine slide 40 may be slid forward to advancethe tines 57 and may be slid backward to retract the tines 57. In someembodiments, the needle 56 and the tines 57 may be coupled to one ormore servos within the body of the handle portion 27 which areconfigured to actuate the needle 57 and the tines 57, and the needle 56and the tines 57 may be actuated by operating the control element 30and/or the controller 12. In many embodiments, the needle 56 must bedeployed first before the tines 57 can be deployed. The imaging cord 24may be attachable at a proximal end of the handle portion 27 of theimaging component 28 for connection to the controller 12, as previouslydescribed.

The imaging component 28 may comprise a handle portion 29 and an imagingshaft 44. A deflection lever 46 on the handle portion 29 can beretracted in order to downwardly deflect the imaging transducer 20, asshown in broken line in FIG. 3. A needle component release lever 48 maybe coupled to a pair of latches 50 which engage hooks 52 on a bottomsurface of the handle portion 27 of the needle component 26. The needlecomponent 26 may be releasably attached to the imaging component 28 byfirst capturing a pair of wings 58 (only one of which is shown in FIG.3) on the needle shaft 34 beneath hooks 60 on the imaging shaft 44, asshown in FIG. 3A. A bottom surface of the needle handle portion 27 maythen be brought down over an upper surface of the imaging handle portion29 so that the hooks 52 engage the latches 50 to form a completeassembly of the treatment probe 16, where the handle portions togetherform a complete handle, for use in a procedure. After use, the needlecomponent release lever 48 may be pulled in order to release the hooks52 from the latches 50, allowing the handle portions 27 and 29 to beseparated.

In use, as will be described in more detail below, the control element30 may be used to both position (translate) and adjust the size of avirtual treatment region which is projected onto the display 14 of thesystem 10. The control element 30 may be pressed forward (distally) andpressed backward (proximally) in order to translate the position of thetreatment/safety region on the image, for example. The control element30 may be pressed to the left and/or right to adjust the size of theboundary of the treatment/safety region. For example, the controlelement 30 may be pressed to the left to shrink the boundary while thecontrol element 30 may be pressed to the right to enlarge the boundary.Once the virtual boundaries of the treatment/safety region have been seton the real-time image, the needle and tines may be automaticallyadvanced to the corresponding deployment positions by moving the needleslide 36 and tine slide 40 until their movement is arrested by the user,for example, as recommended by the stops. The position of thetreatment/safety region may also be dependent on the location at whichthe physician holds the treatment probe 16 within the target tissue.Thus, advancement of the needle 56 and tines 57 using the slides 36 and40 will result in the proper placement of the needle and tines withinthe target tissue only if the treatment probe position is held steadyfrom the time the boundaries are set until advancement of theneedle/tines is completed. In preferred embodiments, the control element30 may also be manipulated to adjust the length of and/or power deliveryduring a treatment protocol. For example, the control element 30 may bepressed to select a different control menu from one for the adjustmentof the boundaries, and one of the selectable menus may allow the powerdelivery parameters to be adjusted such as by pressing up/down to adjustthe time length for power delivery and pressing left/right to adjust theamount of power delivered. Another menu may comprise a menu fordeploying the needle 56 and the tines 57 by operating the controlelement 30, such as in embodiments where the needle 56 and the tines 57are articulated using one or more servos within the handle component 27of the needle component 26. Yet another menu may be selected to allowthe control element 30 to move a cursor on the display 14. Thus, thecontrol element 30 may be used to virtually size the treatment/safetyregion based not only on the degree to which the tines have beenadvanced, but also the amount of energy which is being delivered to thetarget tissue.

FIG. 4 shows a schematic illustration of the needle component 26 of thetreatment probe 16. As shown in FIG. 4, the needle component 26 maycomprise one or more needle position sensors 37 and one or more tinesposition sensors 41. The needle position sensor(s) 37 may be coupled toa handle end portion of the needle deployment shaft 34. Advancement andretraction of the needle 56 by the slide 36 can thereby be tracked bythe needle position sensor(s) 37. The needle position sensor(s) 37 maygenerate a position signal for the needle deployment shaft 34 which maybe sent to the controller 12 through the treatment cord 22 and fromwhich the position of the needle 56 can be determined. Likewise, thetines position sensor(s) 41 may be coupled to a handle end portion ofthe tines deployment shaft disposed within the needle deployment shaft34. Advancement and retraction of the tines 57 by the slide 40 canthereby be tracked by the needle position sensor(s) 37. The tinesposition sensor(s) 41 may generate a position signal for the tinesdeployment shaft which may be sent to the controller 12 through thetreatment cord 22 and from which the position of the tines 56 can bedetermined. The needle position sensor(s) 37 and the tines positionsensor(s) 41 may comprise any type of position sensor such as a linearencoder, a linear potentiometer, a magnetic sensor, a linear variabledifferential transformer (LVDT) sensor, a rheostat sensor, or a pulseencoder, to name a few. The positions of the needle 56 and/or tines 57may be tracked in real time by the positions sensors 37, 41 and thecontroller 12. The calculated treatment and/or safety boundaries may bedisplayed and adjusted on the display unit 14 as the position of theneedle 56 and tines 57 are tracked and optionally updated if moved.Alternatively or in combination, the needle 56 and tines 57 may betranslated using one or more servo motors which may additionally provideposition information for the needle 56 and the tines 57.

The physician may adjust the control element 30 to locate the boundariesof the treatment/safety region as desired to be shown on the visualdisplay 14.

A particular advantage of this method and system is that the physiciancan manipulate the treatment/safety boundaries over the target anatomyby either moving the boundaries relative to (or within) the real-timeimage by manipulating (pressing forward/backward, left/right) thecontrol element 30 or moving the entire real-time image with respect tothe target anatomy by manipulating the entire treatment probe 16 inorder to get the treatment boundary over the tumor and keeping thesafety boundary away from sensitive anatomy. So, before the physicianadvances any needles into the patient tissue, they can confirm inadvance using the virtual targeting interface that the ablation will beeffective and safe.

Referring now to FIG. 5, the system 10 of the present invention can beused to treat a fibroid F located in the myometrium M in a uterus Ubeneath a uterine wall UW (the endometrium) and surrounded by theserosal wall SW. The treatment probe 16 can be introduced transvaginallyand transcervically (or alternately laparoscopically) to the uterus, andthe imaging transducer 20 deployed to image the fibroid within a fieldof view indicated by the broken lines.

Once the fibroid is located on the display 14, as shown in FIG. 6A, thecontrol element 30 on the handle component 27 can be used to locate andsize both a treatment boundary TB and a safety boundary SB. Initially,as shown in FIG. 6A, the virtual boundary lines TB and SB may neither bepositioned over the fibroid nor properly sized to treat the fibroid, andthe control element 30 may be in a neutral position as shown in FIG. 6B.Prior to actual needle and tine deployment, the physician may want toboth position and size the boundaries TB and SB for proper treatment. Asthe imaging transducer 20 may already be positioned against the uterinewall UW, the only way to advance the treatment and safety boundaries TBand SB is to move the boundaries forward by manipulating the controlelement 30, such as by pressing the control element 30 forward in thedirection of arrow UP as shown in FIG. 7B. This manipulation may causethe treatment and safety boundaries TB and SB to move forwardly alongthe axis line AL. This manipulation may also cause the virtualboundaries on the real-time image display 14 to move over the image ofthe fibroid, as shown in FIG. 7A. If the treatment and safety boundariesTB and SB need to be retracted, the control element 30 may bemanipulated such as by pressing the control element 30 backward in thedirection of arrow D as shown in FIG. 7B.

As shown in FIG. 7A, however, the size of the treatment boundary TB maybe insufficient to treat the fibroid since the boundary does not extendover the image of the fibroid. Thus, it may be necessary to enlarge thetreatment boundary TB by manipulating the control element 30, as shownin FIG. 8B, such as by pressing the control element 30 to the right inthe direction of arrow R+. This may enlarge both the treatment boundaryTB and the safety boundary SB, as shown in FIG. 8A. While the enlargedvirtual treatment boundary TB may now be sufficient to treat thefibroid, the safety boundary SB has extended over the serosal wall SW,as also shown in FIG. 8A. Thus, there may be a risk that the treatmentwould affect more sensitive tissue surrounding the uterus, and it may benecessary that the virtual safety boundary SB be retracted by againmanipulating the control element 30 in an opposite direction, such as bypressing the control element 30 to the left in the direction of arrow L−as shown in FIG. 9B. This manipulation may reduce the size of both thesafety and treatment boundaries SB and TB, as shown in FIG. 9A, and thephysician may have confirmation that the treatment may be effectivebecause the treatment boundary TB completely surrounds the fibroid onthe real-time image display, and that the treatment will be safe becausethe safety boundary SB is located within the myometrium M and does notcross the serosal wall SW on the real-time image display.

While holding the treatment probe 16 steady, the physician may thenadvance the needle slide 36, as shown in FIG. 10B, causing the needle 56to extend into the fibroid F, as shown in FIG. 10A. The illustration inFIG. 10A includes a representation of the treatment probe 16 which maycorresponds to the physical probe which is present in the patient. Theremainder of FIG. 10A corresponds to the image present on the targetdisplay 14. The treatment and safety boundaries TB, SB may determine avirtual stop indicator or fiducial 142 for the needle 56. The targetdisplay 14 may include a position indicator 140 for the needle 56, inmany cases the tip of the needle 56. In some cases, the positions of thevirtual stop indicators or fiducials may correlate with the size andposition of the treatment and safety boundaries TB and SB. In othercases, the positions of the virtual stop indicators or fiducials may beadjusted independently with respect to the treatment and safetyboundaries TB and SB.

After the needle 56 has been fully deployed as indicated by the overlapof the needle position indicator 140 and the stop fiducial 142, thetines 57 may be deployed by advancing the tine slide 40, as shown inFIG. 11B. Optionally, the treatment probe 16 may be rotated about acentral axis (typically aligned with the axis of the needle 56) toconfirm the treatment and safety boundaries TB, SB in all planes of viewabout the fibroid. The needle 56 and the tines 57 may remain in placerelative to the fibroid F while the remainder of the treatment probe 16is rotated about the fibroid F. Display 14 may show the position of thetreatment and safety boundaries TB and SB in real time relative to thetarget fibroid F and serosal wall SW. The tines may be configured asshown in FIG. 11A, and power can be supplied to the tines 57 (andoptionally the needle 56) in order to achieve treatment within theboundary depicted by the virtual treatment boundary TB. Again, FIG. 11Amay mix both the virtual image which would be present on the display 14as well as the physical presence of the treatment probe 16.

With the needle 56 and the tines 57 in the desired position, thetreatment probe 16 may be operated to begin ablation of the targetfibroid F. The position of the imaging transducer 20 relative to thetarget fibroid F may be fixed throughout the ablation. Because of thefixed relative position of the imaging transducer 20, for example,real-time images of the treatment space, including the target fibroid Fand the serosal wall SW, can be accurately compared at different timepoints across the ablation process.

FIG. 12 shows a diagram of the tissue treatment system 1200. The user USmay operate the controller 12, which as discussed above may be coupledto the treatment probe 16 to advance or retract the needle structure 56and the plurality of tines 57, i.e., the ablation element, as shown bythe ablation element advancement control 16 a. The user US may alsooperate the controller 12, through the treatment probe 16 in many cases,to start or stop ablation with the needle structure 56 and the pluralityof tines 57, as shown with the ablation control 16 b. As further shownby FIG. 12, the controller 12 may also operate the imaging source 20 toacquire one or more ultrasound images. In many embodiments, the imagingsource 20 acquires both one or more B-mode ultrasound images and one ormore Doppler mode ultrasound image, which the controller 12 may directthe system display 14 to show as a combined image showing both tissuemorphology and blood perfusion. The imaging source 20 may be directed toacquire B-mode ultrasound images and Doppler mode ultrasound images atintervals. For example, ultrasound images may be acquired at a rate of 1to 100 frames per second, with the frames alternating between B-mode andDoppler mode.

FIG. 13 shows a method 1300 for treating a tissue according to thepresent disclosure. The systems and devices described herein may be usedto implement the method 1300, including any combination of the steps andsub-steps thereof.

In a step 1301, a target tissue structure, such as target fibroid F, maybe located.

In a step 1306, a real-time display of the target tissue structure maybe displayed as described herein. In some embodiments, a contrast agentmay be introduced to the target tissue to enhance the image of thestructural and morphological features of the target tissue such thatthey may be better tracked during the ablation. In some embodiments, thefeatures of the Doppler ultrasound image indicating blood perfusion maybe enhanced as well. Contrast agents that may be appropriate may includesome commercially available contrast agents such as Optison®, Definity®,Echovist®, Sonazoid® and SonoVue®, to name a few.

In a step 1311, one or more ablation elements, such as the needlestructure 56 and the plurality of tines 57, may be advanced into thetarget tissue.

In a step 1316, the initial blood perfusion level of the target tissuemay be determined, such as by observing and/or quantifying a Dopplerultrasound image which may be taken by the imaging source 20.

In a step 1321, the target tissue may be ablated for a predeterminedtime period, for example, 0.5 to 20 minutes for a single ablation.

In a step 1326, the blood perfusion level of the target tissue may bedetermined after the predetermined treatment time period. For example,the user may manually make this determination by viewing the updatedreal-time image including Doppler ultrasound and/or contrast enhancedultrasound information. Alternatively or in combination, the controller12 may include be configured to quantify the current level of bloodperfusion and direct the display 14 to show the quantified amount ofblood perfusion.

In a step 1331, this current “post-ablation” blood perfusion level maybe compared to the initial blood perfusion level. If the current bloodperfusion level is not below a threshold as compared to the initialblood perfusion level, the step 1321 of ablating the target tissue andso forth may be repeated. If the current blood perfusion level is belowthe threshold, the protocol may proceed to a step 1336 whereby theablation of the target tissue is ended. The threshold may comprise, forexample, 50% or less, 45% or less, 40% or less, 35% or less, 30% orless, 25% or less, 20% or less, 15% or less, 10% or less, or 5% or lessof the initial blood perfusion amount of the target tissue. In someembodiments, a 30% or more reduction of blood perfusion (i.e., currentblood perfusion level being 30% or less of the initial) may beconsidered a successful treatment.

In some embodiments, the perfusion monitoring of the ablation boundaryduring the treatment is used as a treatment guidance tool. The ablationmay be stopped if the user or system observes that the treatment areahas propagated outside the targeted area. A contrast agent enhancedimage may also facilitate such user observation. The ablation may beinterrupted or halted manually or automatically to ensure patientsafety.

Finally, in a step 1341, the ablation elements, typically the needlestructure 56 and the tines 57, may be retracted form the target tissue.The treatment probe 16 may then be retracted from the surgical fieldentirely, or may be repositioned to treat another target tissuestructure.

Although the above steps show method 1300 of treating tissue in apatient according to many embodiments, a person of ordinary skill in theart will recognize many variations based on the teaching describedherein. The steps may be completed in a different order. Steps may beadded or deleted. Some of the steps may comprise sub-steps. Many of thesteps may be repeated as often as beneficial to the treatment.

One or more of the steps of the method 1300 may be performed withcircuitry within the controller 12, the treatment probe 16, or withinanother system component. The circuitry may comprise one or more of aprocessor or logic circuitry such as the programmable array logic or afield programmable gate array. The circuitry may be programmed toprovide one or more of the steps of the method 1300, and the program maycomprise program instructions stored on a non-transient computerreadable memory or programmed steps of the logic circuitry such as theprogrammable array logic or the field programmable gate array.

FIGS. 14A through 14D show exemplary real-time images of a targetfibroid F during the ablation protocol as described herein. As describedherein, these real-time images may comprise a B-mode ultrasound imageshowing tissue morphology overlaid with a Doppler mode ultrasound imageshowing blood perfusion as taken at various time points.

FIG. 14A shows a first real-time image 1400 a showing the uterus U andthe target uterine fibroid F. A treatment boundary TB may have beenestablished to surround the target uterine fibroid F. The treatmentboundary TB may be centered on the location of the ablation element(s),such as the needle structure 56 and the plurality of tines 57 extendingtherefrom. The first real-time image 1400 a shows the treatment spacebefore any ablation has occurred, and with the Doppler signal(s) 1410received and shown on the image 1400 a defined as a 100% initial Dopplersignal. The level of the Doppler signal(s) 1410 within the treatmentboundary TB may be determined. In the first real-time image 1400 a, forexample, 80% of the initial Doppler signals 1410 may be within thetreatment boundary TB. As discussed herein, the Doppler signal(s) 1410indicate areas of high blood perfusion. In some embodiments, thetreatment boundary TB may be determined and/or adjusted based on thedistribution and/or location of the Doppler signal(s) 1410 showing highblood perfusion. For example, the outer extent of treatment boundary TBmay be selected to capture a majority of the high blood perfusion areas,and/or the treatment boundary TB may be centered on a high perfusionarea as a focal area of the ablation. The treatment boundary TB and thesafety boundary SB may be adjusted with the controller 12 and/ortreatment probe 16 as described above.

FIG. 14B shows a second real-time image 1400 b showing the uterus U andthe target uterine fibroid F after a first time period of ablation. Asshown in the second real-time image 1400 b, an ablated area 1450 b maynow be present within the treatment boundary TB. The ablated area 1450 bmay be visible on the B-mode image component of the real-time image 1400b and/or may be visible on the Doppler mode image component of thereal-time image 1400 b with no Doppler signal within the boundaries ofthe ablated area 1450 b. The level of the Doppler signal(s) 1410 may bereduced after the first predetermined time period of ablation. In thesecond real-time image 1400 b, for example, the total level of theDoppler signals 1410 may be 75% of the initial level shown by FIG. 14A.In some embodiments, the level of the Doppler signal(s) 1410 within thetreatment boundary TB may be determined and compared to the initiallevel to determine a completion percentage of the treatment.

FIG. 14C shows a third real-time image 1400 c showing the uterus U andthe target uterine fibroid F after a further time period of ablation. Asshown in the third real-time image 1400 c, the ablated area 1450 cwithin the treatment boundary TB may now be even larger than before, andthere may now be 50% of the initial Doppler signal(s) 1410. Again, thelevel of the Doppler signal(s) 1410 within the treatment boundary TB maybe determined and may be used to determine a completion percentage ofthe treatment.

FIG. 14D shows a fourth real-time image 1400 d showing the uterus U andthe target uterine fibroid F after yet a further time period ofablation. As shown in the fourth real-time image 1400 d, the ablatedarea 1450 d within the treatment boundary TB may now nearly match thetreatment boundary TB, and there may be very little to none Dopplersignal(s) 1410 with the treatment area TB, indicating that the treatmentor ablation of the uterine fibroid F is complete. The relative level ofthe Doppler signal(s) within the treatment boundary may be used as anindicator of ablation or treatment completion. For instance, theablation or treatment may be indicated as complete if the Dopplersignal(s) 1410 currently within the treatment boundary TB has beenreduced to 50% or less, 45% or less, 40% or less, 35% or less, 30% orless, 25% or less, 20% or less, 15% or less, 10% or less, or 5% or lessof the initial level of Doppler signal(s) 1410, i.e., blood perfusion,within the treatment boundary TB. The exact percentage may beuser-selected based on his or her preference. In some embodiments, thecontroller 12 may allow the user to enter this selection as an ablationparameter to be displayed and tracked. Also, there may still be Dopplersignal(s) 1410 outside of the treatment boundary TB. As shown in FIG.14D, the total level of Doppler signal(s) 1410 within the overall imageis 20% of the initial level.

While preferred embodiments of the present invention have been shown anddescribed herein, it will be obvious to those skilled in the art thatsuch embodiments are provided by way of example only. Numerousvariations, changes, and substitutions will now occur to those skilledin the art without departing from the invention. It should be understoodthat various alternatives to the embodiments of the invention describedherein may be employed in practicing the invention. It is intended thatthe following claims define the scope of the invention and that methodsand structures within the scope of these claims and their equivalents becovered thereby.

1.-20. (canceled)
 21. A method of treating a target tissue, the methodcomprising: ablating the target tissue; monitoring a progress of theablating of the target tissue by viewing a real-time image of the targettissue to monitor blood perfusion of the target tissue.
 22. A method asin claim 21, wherein monitoring the progress of the ablating of thetarget tissue by viewing the real-time image of the target tissue tomonitor blood perfusion of the target tissue comprises determining aninitial blood perfusion level of the target tissue, determining areal-time blood perfusion level of the target tissue, and comparing theinitial and real-time blood perfusion levels of the target tissue.
 23. Amethod as in claim 22, wherein comparing the initial and real-time bloodperfusion levels of the target tissue comprises determining whether thereal-time blood perfusion level of the target tissue is below theinitial blood perfusion level by a threshold amount.
 24. A method as inclaim 23, further comprising halting the ablating of the target tissueonce the blood perfusion of the target tissue is below the thresholdamount.
 25. A method as in claim 23, wherein the threshold amount is 50%or less, 45% or less, 40% or less, 35% or less, 30% or less, 25% orless, 20% or less, 15% or less, 10% or less, or 5% or less of an initialblood perfusion amount of the target tissue.
 26. A method as in claim22, wherein the initial blood perfusion level comprises an initialDoppler ultrasound signal within the target tissue.
 27. A method as inclaim 22, wherein the real-time blood perfusion level comprises areal-time Doppler ultrasound signal within the target tissue.
 28. Amethod as in claim 21, further comprising fixing a position of animaging source in relation to the target tissue.
 29. A method as inclaim 28, wherein the real-time image of the target tissue is generatedduring the ablating with the position of the imaging source fixed inrelation to the target tissue.
 30. A method as in claim 29, wherein thetarget tissue is ablated with an ablation element.
 31. A method as inclaim 30, wherein the imaging source is fixedly coupled to the ablationelement.
 32. A method as in claim 30, wherein the imaging source isremovably coupled to the ablation element.
 33. A method as in claim 21,wherein the real-time image of the target tissue comprises at least oneultrasound image of the target tissue.
 34. A method as in claim 33,wherein the at least one ultrasound image comprises one or more of acontrast enhanced ultrasound image, a B-mode ultrasound image, or aDoppler ultrasound image.
 35. A method as in claim 34, wherein the atleast one ultrasound image comprises a B-mode ultrasound image and aDoppler ultrasound image overlaid over one another.
 36. A method as inclaim 21, wherein the target tissue is ablated with one or more of RFenergy, thermal energy, cryo energy, ultrasound energy, HIFU energy,optical energy, laser energy, X-ray energy, or microwave energy.
 37. Amethod as in claim 21, wherein ablating the target tissue comprisesextending at least one ablation element into the target tissue.
 38. Amethod as in claim 37, wherein the at least one ablation elementcomprises one or more of at least one needle or at least one tine.
 39. Amethod as in claim 21, wherein the target tissue comprises a fibroid, auterine fibroid, a fibroid tissue, a tumor, a tissue hyperplasia, or anundesired scar tissue.
 40. A method as in claim 21, further comprisingintroducing a contrast agent into the target tissue prior to theablation. 41.-60. (canceled)